Testing apparatus for explosion-proof devices



c. w. STARKER.

v I TESTING APPARATUS FOR EXPLOSION PROOF DEVICES.

APPLICATION FILED l/ \N. 26, I9l7- a Patented Nova 14, 1922.

WITNESSES: (2% A I INVENTOR Char/e5 \Sm/w ATTORNEY Patented Nov. 14,192",

CHARLES 'W."STARKEE, F PITTSBURGH,

c i -ea er mmsmvmie; .J'a'ssrsimlt mo 'wnsr'mw VANIA;

i V TESTUING LAPZPARATUS narriiosion-eaaoor ianvronsi Applicationfiledleaner 2 191 7. serialiNoni'Mfi fi,

To (all whom it may concern.

Beit known that L'Cuixmins W.. STARK- R, a suhjectoi the Emperor ofGermany, and a resident ofiPijttsbuitgjhr in the county of Allegheny andStateoffPennsylvania,have invented a new and useful Improvement in'llesting Apparatus for Explos'ion-ProofDevices, of ,n 'h-ichthefollowing is a specification. 7 v I My invention relates to testingapparatus for explosion-proof vdevices uch as are. used in connectionwith electrical apparatus, and it has for its object toploviol'eatestinga'pparatus by meansfoi which the effectiveness ofsi ch devicesmay hei aclily ascertained hefore using them actual service.

.In my copencling application, Serial No. 117,778 filed August 30, 1916,have shown and (lescribeclan eripjlosion-proof devicethat is adapted to"be applied to the enclosing casings of electrical apparatus which isopen atecl in coal mines, tunnels, submarine boa-ts, or in similarlocations where reaclilyhim flammable mixtures "of eXplosive' gases arepresent. The cleviceis so constructed that, when an explosion occursWithin the e-nclos ing easing, the excessive pressure resultingtherefrom is relieved 'Withontjtheemission of-bnrning gasesfzfroin thecasing intothe snrroni-icling atmosphere. I r

Accordingjto the present.invention l provivle a testing apparatuswhereby "explosion- P170015 devices of the 'ahove-clescribecl typeniayhe subjected-to conditions-closely apice,,so that the durability andeffectiveness of such devices may he cleterininetl -heffore placing themon electrical apparatus.

The single figure "of 'the;- accompany ng testing apparatus T embodyingI my invention. The testing apparatus compr ses ahollow cylindricalportion '1, preferably composed of steel of high tensile strength, and,Iiendplate 2 that isljoined totheeylincler lfihy welding; or othersimilar means, sothat a perfectly gas-tight joint is j formecltherehetween, 01' the end-plate'Qmay'be formeil'integral' with thecylinder; 1 The cylinder 1 is internallythreadedto receive an exterpreaching those encounter-jecl in aetnal-serv drawings is a transversesectional vievvof the plate 3 and@terrnin'ates cari'eclshielcl i A COll'81s lQClZLtBCl-Wltllllllllfi flange 4 and ,,curerlgnpon a .re'cluc'eclportion 9 oitho *hiihfi by means of a retaining ring 10; The '1 coil 81s preiierably formed or aflnuniloerfof con'volutions 11 0f strapmaterial that, are spaced apart by sultable means tojprovicle.

passag'es'11 therebet'iveen. 'Theparts ofthe I platefi "an clthe-vcoilS- are, shown as heing', .snbsta11tially thesameiin form as theeorrespending parts e f-the explosion-moot device Cle1seribec'l in myabove mentionedcepenoling application, ,flontitis to, he understood thatthe plate 6 ;jnaay as Well be adapted torece/rive rQlZllGT "similardevices.

The cplate 3isxnormally the fixed end plate- 2 i and an I externallythreaded end plate 12, thereby providing enelosedfancl substantiallyair-tight chambers 13, and. 1-1 at the respective sidesot- Lthe plate'The'end platesZ encl- 12 are respectively located between 7"provieleclfl j with centrally looatecl I openings 15' within which areseateclvalves 16.

she valves '16 are mounted on a rod "17 which k-extenrls through thechanihersplfi and; 14

and [through an; opening -.18 {provided in the hub '5 of the plate Thejrocl 17' is maintainecl inl fixecl relation to tl epplaj-te means i ofcollar "17? a-ncl aulock-nn t '19, enacting, I Lwith aithreaded portionof the rod andthe,

"are held int-he openings 15 by means-er sprineqsQO'fand nuts 21coacting with the real-l7; jThefenc lplates2 anclf12are'further 7provided with openings '22 within {which are locate'clthestems ofsuitable pressure gauges for inclicatorsl23. f'llhe Wall= oif'ithecylinder isjprovidecl' with openings 25hatpoiirts at the respectivesidesof the l?, te"' ,-Within [which arelo'catedthe ends of pi-p es 25that are connected to a: suitable gas 3 2 1513:

through control valves 26,1 The cha nhers and 114 are provided fivithignition 'cle -hers, ot a singlepogle; 'clouh'le throw switch 29." "TlJQl-DIOVT JJblG contact jmeinhei semi" "switchis connectecltooneterrninal grille seconda ry'Winding--30 of an in l'uotion ,coil

31; 'LOne terminal. of the primary winding 8231s connected toasounce-of"electrom'ot ve I 'force throngliia suitable interrupterxiiwindings St) and 352, the source 33 and the cylinder 1. are all.connected to ground, as is customary in similar ignition systems.

7 Having fully described the various parts entering into my invention,the operation thereof is as follows. The plates 3 -.and 12 are sopositioned within the cylinder 1. that the cubic capacity of the chamber13 corresponds to the cubic capacity of the enclosing casing of a pieceof electrial apparatitis, for each unit of the explosion-proof devicewith which it is to be provided. The valves 16 are then. set for themaximum pressure hat is to be permitted within the enclosing casing. Thechambers 13 and 1-4: are then filled with'an explosive gaseous mixture,the composition of which closely approximates the composition of themost ii'iflammable mixture that is liable to be encountered in theservice in which the device to be test ed is to be used. The chargwithin the chamber '13 is exploded by the spark plugQT when the switch29 is thrown to its righthand position and, if the device under test iseffective, the pressure in the chamber 13, following the explosion, willbe relieved more 7 or less gradually, as indicated by the gauges 23. Theswitch29'is then thrown to its lefthand position to cause discharge fromthe plug 28 in order to ascertain whether the charge in the chamber A,isstill of an explo- From the foregoing, it is apparent that ex-.

plosion-proof devices may be subjected to a most rigorous test underconditions closely approaching those encountered in actual service and,while 1. have shown my invention in a simple and preferred form, it isnot so limited but is susceptible of various modifications within thescope or". the appended claims I claim as my invention: v 1. A testingapparatus proof devices comprising two chambers adaptedto be filled withan explosive gaseous mixture and apartition separating said I chambersfor holding the device to be tested andmeans disposed within one of saidchamhers for causing an explosion therein.

[ 2. A testing apparatus for explosionprootdevices comprising aplurallty of commumcatmg chambers adapted to be filled with an explosivegaseous mixture, means disposed within one of said chambers for forexplosioir v oausing an explosion therein thereby etl'ecting equalinternal pressure in each of said chambers to the other. 1

3. A testing apparatus for explosioir proof. devices comprising twochambers adapted to befilled with an explosive gaseous mixture, a 1partition separating said chambers and provided with an opening withinwhich 1s located the device to be tested and means disposed withinone'of said chambers for causing an explosion therein.

4. A testing apparatus for explosion proof devices comprising twochambers adapted to be charged with an explosive gaseous mixture,a'partition separating said chambers and provided with an opening withinwhich located the device to be tested and means disposed within one 01":said. chambers for igniting the charge in one of said cylinders. V

5.1; testing apparatus for explosionproof devices comprising twochambers adapted to be charged with an explosive gaseous mixture, apartition separating-said chambers and provided with an opening withinwhich is located the device to be tested and means for successively andindependently igniting the charges in said chambers.

6. A testing apparatus for explosionproof devices comprising twochambers adapted to be filled with an explosive gaseous mixture, apartition separating said chambers and provided with. an opening withinwhich is located the device to be tested and ignltion device located inone of said chambers.

1A testing apparatus for explosionproot devices 1 comprising twochambers adapted to be filled with an explosive gaseous mixture, apartition separating said chambers and provided with an opening withinwhich is located the device to be test ed. ignition devices located insaid chambers and means for successively operating said devices.

8. A testlng apparatus COHIPYlSlng two substantially gas-tight, chambersseparated by a partition adapted to support a device to be tested, thesaid partition being adjustable or varying the cubic capacities of. saidchambers.

- 9. A" testing apparatus comprising a hollow cylinder provided with endclosures, andv a partition with threaded, engagement with said cylinderfor dividing it into chambers, the said partition being adjustable withrespect to said end closures forvarying the cubic capacities of saidchambers.

In testimony whereof, I have hereunto subscribed my namethis 19th. dayof Jan uary, 1917.

CHARLES W. STARKER.

